1. Field of the Invention
This invention relates to systems which render ships and boats unsinkable.
2. Description of the Related Art
The prior art is aware of supplementary devices which inflate automatically or manually to provide additional buoyancy in the event of water leakage into the vessel. The following is a brief description of the prior art which is pertinent to the present invention.
U.S. Pat. No. 3,121,888 to Morgan et al discloses a protected inflatable member present along the top of the outside surface of the hull. When needed, this inflatable member is filled with gas from a pressurized air cylinder in order to provide a buoyant bag along the top of the boat to keep the boat afloat
U.S. Pat. No. 4,512,275 to Drumm discloses a boat which is unsinkable because it is made of polyethylene foam, which will not sink even though the hull becomes filled with water.
U.S. Pat. No. 4,817,555 to Meinen discloses a boat containing a canister of compressed air which is automatically actuated by the rising of a float inside the boat. Upon opening of the canister, longitudinal bags along the top of the hull outside the boat are inflated to keep the boat afloat.
U.S. Pat. No. 4,864,961 to Slonski discloses an auxiliary flotation apparatus for vessels which comprises canisters connected to a source of compressed air, an inclinometer, and an independent power source. When needed, the compressed air is released into the canisters. When pressurized air enters the canisters, a projectile is propelled away from each canister. The projectile ruptures a frangible membrane located flush with the hull of the vessel. The projectile goes beyond the vessel and carries with it an attached inflatable tubular sheath. One end of the tubular sheath is attached to the hull of the vessel. The sheath becomes filled with air from the source of compressed air, providing a buoyant bag on the outside of the vessel to maintain the vessel afloat.
U.S. Pat. No. 5,357,888 to Insinna discloses a vessel having an elongated inflatable buoyancy tube located on the outside of the hull. The tube is connected to a source of compressed air which, when automatically or manually activated, provides air to the buoyancy tube to keep the vessel afloat.
Of the above patents, one prevents boats from sinking because the boat is made from foam plastic. The other patents disclose buoyant bags fitted to the outside of the craft. These bags can do nothing to affect the entry of water into the craft, and they do no more than merely provide buoyancy.
U.S. Pat. No. 4,458,618 to Tufflier is the prior art of which the inventor is aware which is the closest to the present invention. This patent discloses vessels having enclosed areas such as cabins. The vessels are equipped with three inflatable envelopes. A compressed air container is attached to the three envelopes so that, when needed, the envelopes may be automatically or manually inflated to render the boat buoyant. If the event causing water within the craft is a hole in the hull, the inflated envelopes do nothing to keep the water from continuing to come in. Also, repeated contact with the original cause of the damage could cause puncture of one of the envelopes, causing the boat to be capsized.
A common cause of sinking in vessels is a rupture in the hull. As a result of the rupture, water enters the hull or the space between a double-walled hull and replaces the air. The added weight of the water eventually causes the vessel to weigh more than its volume of water, and sinking results. A way to avoid sinking is to provide bags of air either within the confines of the hull of the vessel or between the walls of a double-hulled vessel. These bags may provide the necessary buoyancy to keep the vessel afloat and/or apply sufficient pressure against the hull as to prevent the entry of water. It is the purpose of the present invention to provide three alternative systems for performing these functions. The time required for a ship to sink is related to the size of the ship and the size of rupture. According to the present invention, while water is filling the hull, air is being forced into air bags by a compressor. Ultimately, the buoyant effect of the filling air bags will meet with the sinking effect of the incoming water. As the compressor is able to compress air at a higher pressure than the incoming water, the bags will begin to expand into areas occupied by water and to push water back out of the rupture. According to the present invention, the air bags are mounted so that when inflated to a maximum pressure, they will be six inches from the inner wall of the hull. This distance reduces the possibility of a piercing of the bags by jagged edges of the rupture while rendering the vessel sufficiently buoyant to remain afloat and operative. The system of the present invention thus gives the crew adequate time to repair the rupture and render the vessel seaworthy.